Minivans and recreational vehicles frequently have rear liftgates that are pivotally mounted to the vehicle frame at the rear of the vehicle. The liftgate is pivotally mounted to the frame by top hinges to allow the liftgate to move between open and closed positions.
Manually operated liftgates and power operated liftgates are well known. Power operated liftgates can be opened and closed manually if a vehicle user so desires. Power operated liftgates are typically driven in opening and closing directions by an electrical motor that is operatively engagable with the liftgate through a series of gears. At least one gear is movably mounted for movement between engaging and disengaging positions so that the motor is operatively connected to the liftgate when the gears are engaged so the liftgate can be moved in opening and closing directions by the motor and is disconnected from the liftgate when the gears are disengaged so the liftgate can be opened and closed manually without backdriving the motor. Examples of typical systems include U.S. Pat. Nos. 5,448,856 and 5,563,483.
The movable gear may have a tendency to move out of engagement when the motor is either opening or closing the liftgate, depending on the particular geometry. This is undesirable because movement of the movable gear can result in gear slippage and/or in excessive gear noise.